EP0121530B1 - Verfahren und ofen zur graphitisierung - Google Patents

Verfahren und ofen zur graphitisierung Download PDF

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Publication number
EP0121530B1
EP0121530B1 EP83903091A EP83903091A EP0121530B1 EP 0121530 B1 EP0121530 B1 EP 0121530B1 EP 83903091 A EP83903091 A EP 83903091A EP 83903091 A EP83903091 A EP 83903091A EP 0121530 B1 EP0121530 B1 EP 0121530B1
Authority
EP
European Patent Office
Prior art keywords
column
products
furnace
carbonaceous
zone
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP83903091A
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English (en)
French (fr)
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EP0121530A1 (de
Inventor
Jean-Claude Bernard
Patrick Chabrier
Bernard Tahon
Jean-Marc Tesoriere
Domingo Ortega
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Pechiney Balzac
SGL Carbon SA
Original Assignee
Societe des Electrodes et Refractaires Savoie SA
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Publication date
Application filed by Societe des Electrodes et Refractaires Savoie SA filed Critical Societe des Electrodes et Refractaires Savoie SA
Priority to AT83903091T priority Critical patent/ATE19232T1/de
Publication of EP0121530A1 publication Critical patent/EP0121530A1/de
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Publication of EP0121530B1 publication Critical patent/EP0121530B1/de
Expired legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/52—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbon, e.g. graphite
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
    • D01F9/145—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues
    • D01F9/155—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments from pitch or distillation residues from petroleum pitch
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
    • D01F9/32—Apparatus therefor
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F9/00—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments
    • D01F9/08—Artificial filaments or the like of other substances; Manufacture thereof; Apparatus specially adapted for the manufacture of carbon filaments of inorganic material
    • D01F9/12—Carbon filaments; Apparatus specially adapted for the manufacture thereof
    • D01F9/14—Carbon filaments; Apparatus specially adapted for the manufacture thereof by decomposition of organic filaments
    • D01F9/32—Apparatus therefor
    • D01F9/322—Apparatus therefor for manufacturing filaments from pitch
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B9/00—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity
    • F27B9/28—Furnaces through which the charge is moved mechanically, e.g. of tunnel type; Similar furnaces in which the charge moves by gravity for treating continuous lengths of work
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B3/00—Ohmic-resistance heating
    • H05B3/60—Heating arrangements wherein the heating current flows through granular powdered or fluid material, e.g. for salt-bath furnace, electrolytic heating
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/25—Process efficiency

Definitions

  • the process which is the subject of the invention relates to the graphitization of long carbon products, in order to obtain electrodes, elongated bars, tubes of circular or other cross section, or any other long graphite products.
  • the invention also relates to an oven for implementing the method according to the invention.
  • the carbonaceous products to be graphitized (1) which, in the case of the figure, are bars of circular section arranged vertically end to end, penetrate into the oven (2) through an inlet orifice constituted by a guide tube (3) and an annular graphite sleeve (4), which is connected to one of the poles of an electric current source.
  • This sleeve has an internal diameter such that there is a large radial clearance between the column of carbon products and it.
  • Such an oven has the drawback of requiring a double circulation of products: on the one hand, the column of carbon products and, on the other hand, the filling coke granule.
  • the circulation of this coke granule is necessary because, if it did not circulate, it would excessively heat up in the upper zone of the furnace where it is traversed by all of the electric current from the sleeve (4); in addition, throughout the column of carbon products, this granule is driven downward both by gravity and by friction. It is therefore important to extract, at the base of the furnace, as regularly as possible, granules maintained at an extremely high temperature by contact with the column of electrodes despite the proximity of the water-cooled walls (11) of the furnace. (1). Likewise, the column of electrodes leaves the furnace at an extremely high temperature owing to the fact that it is traversed by all of the electric current up to the contact parts (7).
  • the continuous process for the graphitization of long precooked carbonaceous products consists in moving along a substantially horizontal axis of travel, these long precooked carbonaceous products, of circular or other cross-section in columns, in an oven whose lining is made of a material divided carbon which is in contact with said column of carbon products but does not accompany it in its movements, the heating of this column of products being ensured by the Joule effect.
  • At least one electrical contact is made at the inlet of the oven between the column of products and one of the poles of a current source, the second pole of the current source being brought into contact with the column of products at l downstream end of the graphitization zone inside the oven.
  • the entire column is placed under compressive stress by exerting on its two ends, by means of pressure such as jacks, forces parallel to the axis of travel and directed one against the other, the intensity of which is between approximately 0.1 and 1 MPa.
  • an electrical current whose intensity is between 10 and 50% of the current flowing through the column is introduced into the column of products, at its upstream end, in the immediate vicinity of the pressure medium. inside the oven.
  • the additional fraction of the current is introduced into the column further downstream, just in the inlet zone of the furnace, in an area where the temperature of the column is already above about 500 ° C.
  • one of the poles thereof is connected in parallel to the product column, at its upstream end, and further downstream in the inlet zone of the furnace, while the other pole of this current source is connected to the column, inside the furnace itself.
  • the first is a preheating current source comprising a first pole connected to the upstream end of the product column and a second pole connected to the product column in the inlet zone of the oven.
  • the second is the actual graphitization source, the first pole of which is connected, like the second pole of the preheating current source, to the column of products in the inlet zone of the furnace, the second pole being connected to this same column inside the oven, at the downstream end of the graphitization zone.
  • alternating current or direct current can be used.
  • the column is brought into electrical contact with the second pole of the graphitization current source is advantageously carried out, according to the invention, at the downstream end of the graphitization zone, by means of at least one electrical connection conductor which penetrates inside the furnace, the axis of which is substantially transverse with respect to the axis of travel of the column of products, of which at least one end remote from the column of carbonaceous products is connected, outside the oven, at the second pole of the current source, another end or another part of this electrical connecting conductor being in direct or indirect contact with the column of carbon products inside the oven.
  • the contact between the column of moving carbon products and the electrical connecting conductor is preferably provided by a layer of divided carbon material, such as graphite grains, which fills the space between this electrical connecting conductor, the side wall of the column of carbon products and the part closest to this electrical connecting conductor.
  • This space has a width of the order of 1 to 10 cm.
  • two or more electrical connecting conductors connected in parallel to the second pole of the current source, suitably distributed around the axis of travel of the column of carbon products.
  • At least one electrical connection conductor can be used which crosses the entire width of the oven. The two ends of this conductor are then connected to the current source, while it is in its middle part in direct or indirect contact with the column of products.
  • a gradual cooling of the column of carbon products is carried out by placing, inside the furnace, downstream of the graphitization zone, within the divided carbon material, at least one thermal bonding conductor which penetrates the interior of the oven, the axis of which is substantially transverse with respect to the axis of the column of products, at least one end of which, remote from the column of carbonaceous products, is preferably outside the oven and is cooled by a cooling means, another end or another part of this thermal bonding conductor being in direct or indirect contact with the column of carbon products inside the oven.
  • This thermal bonding conductor is preferably made of graphite as regards at least the part of it, which is housed inside the oven in the very high temperature zone.
  • thermal connecting conductors distributed suitably around the axis of travel of the column of products and, preferably also, these conductors are distributed along the axis of travel of the column of products downstream of the graphitization zone up to the immediate vicinity of the end of the oven through which the column of products comes out of the oven.
  • At least one thermal bonding conductor can be used which crosses the entire width of the furnace. The two ends of this conductor are then outside the oven and it is its middle part which is in direct or indirect contact with the column of products.
  • the scrolling of the column of carbonaceous products is carried out by exerting on this column a pressure higher on the upstream side than the pressure exerted on the downstream side, and by adjusting this pressure so as to obtain a regular movement of the product column from upstream to downstream, while keeping the column under stress during its movement.
  • This movement can be done at constant or variable speed, or even step by step.
  • this movement is interrupted each time the column of products has moved a length equal to the unit length of a product or to a multiple of this length.
  • One or more graphitized products are then extracted at the downstream end of the column and one or more carbonaceous products to be graphitized at the upstream end are put in place. It is then possible again to restart the scrolling of the column of products inside the oven at the desired speed of displacement after having put the column back under pressure.
  • the invention also relates to a continuous furnace for the graphitization of long carbon products, which comprises an elongated enclosure in the horizontal direction provided, at one of its ends, with an inlet zone through which a column of long carbon products penetrates. to graphitize and, at the other end, an exit zone through which the column of long carbon products leaves after graphitization.
  • the enclosure contains an insulating material consisting of a carbonaceous material divided in contact with the column of products.
  • An electrical contact means comprising an annular piece, through which passes the column of products to be graphitized, placed in the entry area and connected to one of the poles of the current source, makes it possible to introduce at least 50 % of the current in the column of products to be graphitized.
  • Another electrical contact means comprising at least one electrical conductor placed inside the furnace, provides the electrical connection between the column of graphitized products and the other pole of the source of electrical current.
  • at least one thermal contact means comprising at least one thermal conductor, placed inside the oven downstream of the electrical contact means, ensures a thermal bond between the column of graphitized products and a fluid which is located at a temperature close to ambient. The intensity of the electric current flowing through the product column is adjusted so that the temperature of this column in the hottest zone exceeds 2,500 ° C and preferably reaches 3,000 ⁇ 200 ° C.
  • FIG. 2 schematically represents an oven (12) of elongated shape, which comprises, from upstream to downstream, an inlet zone (13) into which the column of long carbon products (14) penetrates which undergoes preheating in this zone, the main part (15), or body of the furnace, in which the column of carbonaceous products (14) is brought to the necessary graphitization temperature, then gradually cooled and, finally, an outlet zone (16) in which the column of products, now in the graphitized state, is further cooled to the desired temperature so that it can be exposed to the air at (17) without inconvenience.
  • a jack (18) On the upstream side, a jack (18), provided with a piston (19), exerts a pushing force on the product column (14) in the direction of arrow F 1 , by means of a part d 'support and electrical contact (20) cooled by internal circulation of a fluid such as water.
  • a jack (21) exerts, by means of its piston (22) which acts on the support piece (23), a retaining force in the direction of the arrow F 2 on the product column in area (17).
  • the pushing and retaining forces are adjusted so that the product column moves from upstream to downstream, that is to say from right to left in the case of FIG. 2 , at the desired speed, while being maintained in compression with a force of approximately 0.1 to 1 MPa.
  • a current source S which may be alternating or direct current, allows an electric current I of sufficient intensity to pass through the column of products to be graphitized so that the carbonaceous products constituting the column are brought to the graphitization temperature. inside the oven.
  • a fraction 1 1 of the current I generally between 10 and 50% of I is introduced at the head of the column of carbon products by means of the support piece (20) which is connected to one of the poles of the electric current source by the conductor (24).
  • the complementary fraction 1 2 is introduced, as shown in FIG. 2, at the level of the inlet zone (13) of the furnace by the conductor (25) which is therefore mounted in parallel with (24).
  • the column of carbon products is connected to the other pole of the current source S via the electrical contact means (26) and the conductor (27).
  • the location of the electrical contact means (26) in the body of the oven (15) delimits, on the upstream side, the length of the graphitization zone G in which the column of carbonaceous products is brought to the desired temperature for transform into graphite. Downstream of the electrical contact means (26), extends over the rest of the length of the body of the furnace, a cooling zone R in which the temperature of the column of graphitized carbonaceous products drops well below the range graphitization temperature.
  • a carbon material divided in the form of grains or powder is used as insulation. This material occupies at least the entire space which directly surrounds the column of electrodes and comes into contact with the latter.
  • refractories based on metal oxides in the form of bricks or refractory concretes.
  • zone G advantageously, as thermal insulator (30), in the immediate vicinity of the column of carbon products, a carbonaceous matter in grains or else a carbon black powder (black cardboard). These two materials can also be used in alternating layers. Experience has shown that, under normal operating conditions, the scrolling of the column of carbon products inside the oven does not cause the divided carbonaceous material to be drawn towards the exit zone from the oven.
  • a divided carbon material 48 (see fig. 5) having a higher thermal conductivity than that it is used in zone G. It is possible to use, for example, coke grains or graphite grains, or a mixture of these grains.
  • At least one thermal conductor constituted by one or more elongated bars, of relatively strong section, of material which is a good conductor of heat, oriented in a direction preferably transverse to the axis of the column of carbonaceous products.
  • These bars are arranged so that at least one of their ends is in the vicinity of the outer wall of the furnace, so that it can be easily cooled by suitable means.
  • the other end of these bars, or a running part of them, is in the immediate vicinity of the product column.
  • graphite bars of sufficient section.
  • Figure 2 shows the end (28) of such a thermal conductor.
  • the number and the section of these thermal conductors are determined to allow the desired cooling rate of the column of graphitized products to be obtained, taking into account its section and its running speed as well as the length of the zone R.
  • the the cooling rate of the column of graphitized products must be lower the higher its section.
  • Figures 3, 4 and 5 show in more detail, in cross section, enlarged along the cutting planes A-A, B-B and C-C, the internal structure of the furnace body.
  • Figure 3 which is an enlarged section along AA of Figure 2, shows the internal structure of the oven in a current part of the graphitization zone G.
  • the column of products being graphitized (29) is entirely surrounded by a material divided carbon (30), low thermal conductivity, grain size of the order of 0.2 to 10 mm.
  • This granule is itself housed inside a lining of refractory bricks (31) surrounded by a sheet metal casing (32). In certain areas, it may be useful to cool the metal casing in a known manner to avoid local overheating which can cause deformation.
  • the divided carbonaceous material is in contact with the ambient air.
  • FIG. 4 is an enlarged section along B-B of Figure 2 to the right of the electrical contact means (26).
  • this electrical contact means consists of two graphite bars (34-35) of circular section, for example, arranged transversely with respect to the axis of the column of graphitized carbon products (29).
  • One end of each of these graphite bars is in the immediate vicinity of the column of products, an interval of a few centimeters (36-37) being preferably provided to avoid any risk of snagging.
  • the other end of each of these bars is outside the oven and is enclosed in an electrical contact part (38-39) cooled by circulation of fluid in a known and not described manner.
  • These two electrical contact parts are connected by the electrical conductor (27) to the second pole of the current source S (see FIG. 2).
  • direct contact can be made between the moving column and these bars.
  • FIG. 5 is an enlarged section along C-C of Figure 2 to the right of the thermal bonding conductor (28).
  • This thermal conductor consists of two graphite bars (42-43) of cross-section, for example circular, arranged transversely with respect to the axis of the column of graphitized carbonaceous products (29).
  • Each of these graphite bars has a zone (one of its ends in the case of the figure), which is in the immediate vicinity of the column of products (29), an interval of a few centimeters (44-45) being preferably arranged to avoid any risk of snagging.
  • the other end of each of these bars is outside the oven and is cooled by a thermal contact part (46-47) provided with a means of cooling by circulation of fluid, not shown.
  • the product column (29) and the graphite bars are surrounded by a divided carbonaceous material (48) such as a coke pellet or other divided carbonaceous material. It is possible, if this proves useful, to improve the thermal contact between the product column and the graphite bars by placing in the intervals (44-45) and in the surrounding space, a divided carbonaceous material of high thermal conductivity such as than a graphite-based granule.
  • the thermal contact between the column of graphite products (29) and the graphite bars can be further improved by making a sliding contact in a manner analogous to that which can be made at the level of the electrical contact bars.
  • thermal bonding conductors along the axis of travel of the product column, at intervals determined so as to obtain the desired curve of temperature drop of the graphite products, taking into account their running speed and their section.
  • the various parameters are adjusted so as to obtain a cooling rate of approximately 4 to 10 ° C./min.
  • it is preferable to reduce the maximum cooling rate so as not to exceed 7 ° C / min.
  • FIG. 6 is an enlarged axial section of the inlet zone (13) of the oven (12) of FIG. 2. It can be seen that the column of carbonaceous products (14) circulates inside this inlet zone ( 13) tubular, in the direction of the arrow.
  • the wall which surrounds the product column, comprises an annular piece of graphite (49) and two annular pieces of an insulating refractory material (50 and 51).
  • An outer sheet steel jacket (52) is cooled by means of a fluid circulation, not shown.
  • This outer envelope is connected to the metal wall (53) of the furnace body by means of an insulating seal, not shown.
  • a metal collar (54) encloses the outer casing (52) in the area where it is itself in contact with the graphite part in its upstream part (55).
  • This collar is connected by the conductor (25) to one of the poles of the current source S (see fig. 2).
  • the transmission of electric current between the graphite part (49) and the column of carbon products (14) is ensured by virtue of a divided carbon material (56) which fills the gap between the column of carbon products (14) and the part downstream (57) of the graphite part (49).
  • This divided carbonaceous material may consist of grains of coke, graphite or other carbonaceous material. It is introduced at the upstream end of the entry zone through the hopper (58).
  • Figure 7 is a sectional view along DD of Figure 6, which shows the flow channel (59) and the distribution of the divided carbonaceous material (56) in the annular space surrounding the product column (14 ). Thanks to the presence of this divided carbonaceous material, the electrical connection between the graphite part in its downstream part (57) and the column of products is ensured around the entire periphery of the column.
  • the upstream part (55) of the graphite part which is in contact with the external cold wall (52), and the product column (14), an annular packing (51) in an insulating refractory.
  • the graphite part is sufficiently elongated so that its downstream part (57) which ensures electrical contact with the column of products via the material divided carbon, can reach in normal operating conditions a high temperature compared to that of the metal casing (52) thanks to the insulating refractory lining (50) which separates it. Thanks to this arrangement, the downstream part (57) of the graphite part reaches a normal temperature of the order of 500 to 1000 ° C., which promotes a regular rise in temperature of the column of products.
  • Figure 8 is an enlarged axial section of the outlet region (16) of the furnace (12).
  • a fluid such as l 'water.
  • annular wall preferably made of graphite (63) is located opposite the column of graphitized products (17).
  • this graphite wall is separated, in its upstream part (64), from the casing (61) by means of a lining of a non-refractory carbonaceous (65).
  • the graphite wall (63) is in direct contact with the cooled envelope (62) so as to allow sufficient cooling of the column of graphitized products before it emerges outside.
  • a layer of divided carbonaceous material (66) fills the annular space between the column of products and the graphite wall.
  • This material is introduced through the hopper (67) which is placed in communication with the annular space at the upstream end of the outlet zone (16) by a bore (68) which passes through the walls (64 and 65).
  • This material is driven slowly by the displacement of the column of products and flows at the downstream end of the tubular enclosure through a chute (69) in a receiving container (70).
  • Suitable recirculation means can take the granule back into this container and reintroduce it into the hopper (67).
  • the introduction of divided carbonaceous material in the immediate vicinity of the downstream end of the furnace body has, in particular, the advantage of preventing any entrainment outside of the divided carbonaceous material (48) contained in the body of the furnace. oven.
  • the divided carbonaceous material which circulates in the outlet zone, may consist of grains of coke, graphite or any other stable carbonaceous material.
  • the cooling speed of the column of graphitized products is adjusted according to the same speeds as in zone R.
  • the cooling speed does not exceed about 10 ° C / min. up to 400 ° C.
  • these carbonaceous products to be graphitized consist of a mixture of carbonaceous grains such as petroleum coke or another carbonaceous material with a suitable binder such as a hydrocarbon compound and / or a synthetic resin and / or another binder .
  • a batch of carbonaceous products prepared by spinning consisting of a mixture of 75% by mass of petroleum coke and 25% of coal pitch is treated in the form of cylindrical bars which, after baking at 800 ° C, have a diameter of 529 mm and a unit length of 2150 mm. In this state, these bars have a resistivity of 6,000 micro-ohms cm. These bars constitute a column of products which are passed through in an oven according to the invention, as shown in FIGS. 2 to 8. At the level of the contacts between the ends of each bar, a thin layer of carbon felt is interposed or compressed expanded graphite to improve electrical contact and to absorb surface unevenness.
  • the column of carbon products consists of a total of 11 bars or sections.
  • the pressure exerted by the jacks on the column of products, during scrolling, is adjusted so that the compressive stress is approximately 0.6 to 1 MPa.
  • the running speed is approximately 1.5 m / h.
  • the intensity of the current flowing through the contact (20) is about 10,000 to 15,000 A, while the intensity of the current flowing through the column in the graphitization area G is approximately 40,000 A.
  • the voltage across the terminals of the alternating current source is approximately 100 V.
  • the inside diameter of the downstream graphite contact piece (57) is approximately 580 mm.
  • the length of the graphitization zone G is approximately 6 m; it is therefore covered in approximately 4 h.
  • the cooling zone R has a length of approximately 4 m and the outlet zone (16) which extends it, a length of approximately 6.5 m.
  • the time for the carbonaceous product constituting the column to pass through the furnace is approximately 12 h without taking account of the downtime required to unload the graphitized sections at the downstream end and set up the sections to be graphitized at the upstream end.
  • the time required to produce a 2,150 m long graphitized section is approximately 1.5 hours, taking into account the stops for changing the electrode. This corresponds to approximately 500 kg of graphitized product per hour. Energy consumption is around 3.5 KWh / kg.
  • the inside diameter of the downstream part (57) of the graphite contact piece in the entry zone (16) is increased to 680 mm.
  • the lengths of the inlet zone, the graphitization zone G, the cooling zone R and the outlet zone, are the same as in Example 1.
  • the pressure exerted on the column in displacement by the jacks (18) and (24) is adjusted to obtain an axial stress of approximately 0.6 to 1 MPa.
  • the intensity of the current flowing through the column of products in the graphitization zone is 55,000 A, and the voltage across the terminals of the alternating current source is approximately 80 volts.
  • the intensity of the current introduced at the head of the column through the contact (20) is approximately 13,000 to 17,000 A, the complement to 55,000 being introduced at the contact (25).
  • the column running speed is 1.0 m / h.
  • a graphitized electrode is therefore extracted from the furnace in approximately 2.5 h, taking into account the stopping time necessary to remove the graphitized section and set up a new section.
  • the hourly production of this oven is therefore around 400 kg / h.
  • the physical characteristics of the products thus graphitized are the same as in the case of Example 1.
  • the oven used can also include numerous variants which do not depart from the scope of the invention.

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Claims (19)

1. Kontinuierliches Verfahren zur Graphitisierung vorgebrannter langer kohlenstoffhaltiger Erzeugnisse, bei dem man diese kohlenstoffhaltigen Erzeugnisse säulenförmig im Inneren eines Ofens durchlaufen läßt, der mit einer Auskleidung versehen ist, die aus einem unterteilten kohlenstoffhaltigen Material (30) besteht und das Innere ausfüllt, wobei die Erhitzung der Säule von kohlenstoffhaltigen Erzeugnissen (14-17) durch direkte Joulesche Wärme bis zu einer Temperatur von wenigstens 2500°C gesichert wird, dadurch gekennzeichnet, daß die Säule der kohlenstoffhaltigen Erzeugnisse (14-17) in horizontaler oder nahezu horizontaler Weise angeordnet ist und daß das unterteilte kohlenstoffhaltige Material (30) im Kontakt mit dieser Säule der kohlenstoffhaltigen Erzeugnissen (14-17) ist, sie aber bei ihrem Durchlauf nicht begleitet.
2. Verfahren nach dem Anspruch 1, dadurch gekennzeichnet, daß die Säule der kohlenstoffhaltigen Erzeugnisse während des Durchlaufs einer Druckspannung von etwa 0,1 bis 1 MPa längs der Durchlaufachse ausgesetzt wird.
3. Verfahren nach den Ansprüchen 1 oder 2, dadurch gekennzeichnet, daß die elektrische Verbindung zwischen der Säule von Erzeugnissen und wenigstens einer Stromquelle an der Stromaufseite auf wenigstens 2 Punkte verteilt wird, wobei ein Anteil von 10-50 % der Stärke des Graphitisierungsstroms am Säulenkopf (20-24) und der restliche Anteil weiter stromab (13-25) eingeführt werden.
4. Verfahren nach einem der Ansprüche 1-3, dadurch gekennzeichnet, daß nach dem Erreichen einer Temperatur von wenigstens 2 500 °C die Säule bis zu einer Temperatur unter oder gleich 400 °C mit einer mittleren Geschwindigkeit abgekühlt wird, die im Fall einer Säule von etwa 500 ± 50 mm Durchmesser 10°C/min nicht übersteigt.
5. Verfahren nach dem Anspruch 4, dadurch gekennzeichnet, daß im Fall einer Säule von etwa 600 ± 50 mm Durchmesser die Abkühlungsgeschwindigkeit 7 °C/min nicht übersteigt.
6. Durchlaufofen zur Graphitisierung langer kohlenstoffhaltiger Erzeugnisse mit einem länglichen Gehäuse, das den Körper des Ofens (12) bildet und das an einem seiner Enden eine Einlaßzone (13) der zu graphitisierenden Erzeugnisse und am anderen Ende eine Auslaßzone (16) aufweist, wobei die Wärmedämmung des Ofens aus einem unterteilten kohlenstoffhaltigen Material (30) besteht, dadurch gekennzeichnet, daß diese Zonen längs einer im wesentlichen horizontalen Achse angeordnet sind, längs deren als Säule (14-17) die zu graphitisierenden Erzeugnisse durchlaufen, die direkt durch Joulesche Wärme erhitzt werden, und daß das unterteilte kohlenstoffhaltige Material (30) im Kontakt mit der Säule der Erzeugnisse (14-17) ist, sie jedoch während deren Durchlaufs nicht begleitet.
7. Ofen nach dem Anspruch 6, dadurch gekennzeichnet, daß er mit Winden (18, 21) oder jedem anderen Mittel ausgerüstet ist, womit die Fortbewegung der Säule mit der gewünschten Durchlaufgeschwindigkeit bei gleichzeitiger Einwirkung einer Druckspannung auf sie ermöglicht wird.
8. Ofen nach den Ansprüchen 6 oder 7, dadurch gekennzeichnet, daß die Kontakte zwischen den Abschnitten der kohlenstoffhaltigen Erzeugnisse, die die Säule bilden, mittels eines Kontaktmaterials, wie z. B. einer dünnen Schicht eines Kohlenstoffilzes oder aus expandiertem komprimiertem Graphit, verbessert sind.
9. Ofen nach einem der Ansprüche 6-8, dadurch gekennzeichnet, daß ein elektrischer Kontakt zwischen der Säule der kohlenstoffhaltigen Erzeugnisse und einem der Pole der Stromquelle in der Einlaßzone des Ofens mittels einer länglichen Muffe (49) aus Graphit hergestellt ist, die die Säule umgibt, wobei deren Stromaufendzone (55) mit der Stromquelle verbunden und thermisch und elektrisch gegenüber der Säule der Erzeugnisse isoliert ist, während das Stromabende (57) den Kontakt mit der Säule der kohlenstoffhaltigen Erzeugnisse sichert.
10. Ofen nach einem der Ansprüche 6-9, dadurch gekennzeichnet, daß ein zweiter elektrischer Kontakt, der mit demselben Pol der Stromquelle wie die längliche Graphitmuffe verbunden ist, mittels eines Kontaktstücks (20) vorgesehen ist, das am Stromaufende der Säule der kohlenstoffhaltigen Erzeugnisse angeordnet ist.
11. Ofen nach einem der Ansprüche 6-10, dadurch gekennzeichnet, daß im Inneren des Ofens am Ende der Graphitisierungszone wenigstens ein quer angeordnetes, längliches Graphitstück (34, 35) die Schaffung einer elektrischen Verbindung zwischen der Säule der kohlenstoffhaltigen Erzeugnisse (29) und dem zweiten Pol der Stromquelle (27) ermöglicht.
12. Ofen nach dem Anspruch 11, dadurch gekennzeichnet, daß wenigstens ein längliches Stück aus Graphit (34, 35) wenigstens ein Ende (38, 39), das außerhalb des Ofens mit der Stromquelle verbunden ist, und einen im Inneren des Ofens in unmittelbarer Nähe der Säule der Erzeugnisse (29) liegenden Teil aufweist, der mit dieser direkt oder mittels unterteilten Kohlenstoffgranulats, wie Graphitgranulats (40), in elektrischem Kontakt ist.
13. Ofen nach einem der Ansprüche 6-12, dadurch gekennzeichnet, daß stromab der Graphitiserungszone wenigstens ein Wärmeverbindungsleiter (42, 43) innerhalb des unterteilten kohlenstoffhaltigen Materials (48) derart angeordnet ist, daß seine Achse im wesentlichen quer zur Durchlaufachse steht, wobei wenigstens sein eines, von der Säule der kohlenstoffhaltigen Erzeugnisse entferntes Ende durch ein Abkühlungsmittel (46, 47) gekühlt wird und ein im Inneren des Ofens liegender Teil dieses Wärmeverbindungsleiters sich in unmittelbarer Nähe der Säule der kohlenstoffhaltigen Erzeugnisse (29) befindet.
14. Ofen nach dem Anspruch 13, dadurch gekennzeichnet, daß der oder die Wärmeleiter (42, 43) aus Graphit ist (sind).
15. Ofen nach dem Anspruch 13, dadurch gekennzeichnet, daß mehrere Wärmeleiter längs der Durchlaufachse zwischen der Graphitisierungszone und dem Stromabende des Ofens angeordnet sind.
16. Ofen nach einem der Ansprüche 6-12, dadurch gekennzeichnet, daß die Säule der Erzeugnisse (14) in der Einlaßzone (13) von einer Schicht aus unterteiltem kohlenstoffhaltigen Material (56) umgeben ist.
17. Ofen nach dem Anspruch 16, dadurch gekennzeichnet, daß er ein Mittel (58) zum Einführen unterteilten kohlenstoffhaltigen Materials (56) am Stromaufende der Einlaßzone (13) und ein Mittel (59) zum Auslaß unterteilten kohlenstoffhaltigen Materials am Stromabende der Einlaßzone (13) aufweist.
18. Ofen nach einem der Ansprüche 6-17, dadurch gekennzeichnet, daß die Säule der Erzeugnisse (17) in der Auslaßzone (16) von einer Schicht unterteilten kohlenstoffhaltigen Materials (66) umgeben ist.
19. Ofen nach dem Anspruch 18, dadurch gekennzeichnet, daß er ein Mittel (67) zum Einführen unterteilten kohlenstoffhaltigen Materials am Stromaufende der Auslaßzone (16) und ein Mittel (69) zum Auslaß unterteilten kohlenstoffhaltigen Materials am Stromabende der Auslaßzone (16) besitzt.
EP83903091A 1982-10-06 1983-10-04 Verfahren und ofen zur graphitisierung Expired EP0121530B1 (de)

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AT83903091T ATE19232T1 (de) 1982-10-06 1983-10-04 Verfahren und ofen zur graphitisierung.

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FR8217020 1982-10-06
FR8217020A FR2534240A1 (fr) 1982-10-06 1982-10-06 Procede continu de graphitisation de produits carbones longs et four pour la mise en oeuvre de ce procede

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FR (1) FR2534240A1 (de)
GR (1) GR79700B (de)
IE (1) IE56122B1 (de)
IN (1) IN159953B (de)
IT (1) IT1167246B (de)
MX (1) MX157341A (de)
NZ (1) NZ205862A (de)
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NO157078C (no) * 1985-08-22 1988-01-13 Elkem As Bakeovn for elektroder.
DE3601014C2 (de) * 1986-01-16 1995-09-07 Vaw Ver Aluminium Werke Ag Verfahren und Vorrichtung zur kontinuierlichen Stranggrafitierung von Kohlenstoff-Formkörpern
IT1191877B (it) * 1986-04-30 1988-03-23 Elettrocarbonium Spa Perfezionamento nei forni di grafitazione mobili
KR890002459A (ko) * 1987-07-31 1989-04-10 오카다 모리오 내염화섬유의 제조방법
NL8801535A (nl) * 1987-09-04 1989-04-03 Nl Omroepproduktie Bedrijf Verbindingsorgaan voor elektrische, informatie bevattende signalen, alsmede werkwijze voor het vervaardigen daarvan.
FR2621311B1 (fr) * 1987-10-06 1992-01-10 Savoie Electrodes Refract Procede et dispositif de graphitisation continue simultanee de produits carbones longs et de grains carbones circulant a contre-courant
AT389506B (de) * 1988-08-04 1989-12-27 Voest Alpine Maschinenbau Verfahren und vorrichtung zum graphitieren von kohlenstoffkoerpern
FR2662496B1 (fr) * 1990-05-22 1992-09-04 Tesoriere Jean Marc Procede et four de graphitisation.
AT393382B (de) * 1990-05-31 1991-10-10 Voest Alpine Mach Const Verfahren und vorrichtung zum graphitieren von kohlenstoffkoerpern
AT393499B (de) * 1990-08-01 1991-10-25 Voest Alpine Mach Const Verfahren und vorrichtung zum graphitieren von kohlenstoffkoerpern
DE102017113342A1 (de) * 2017-06-19 2018-12-20 Eisenmann Se Ofen

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US2621218A (en) * 1951-06-06 1952-12-09 Dow Chemical Co Electric graphitizing furnace
DE2162246C3 (de) * 1971-12-15 1974-11-07 Nukem Gmbh, 6454 Grossauheim Messverfahren zur Bestimmung der Graphitierungstemperatur und des Graphitierungsgrades von graphitierten Kokspulvern und zur Kontrolle der Temperatur und Temperaturverteilung in Graphitierungsöfen
DE2316494B2 (de) * 1973-04-03 1978-05-03 Sigri Elektrographit Gmbh, 8901 Meitingen Hochstromwiderstandsofen
DE2425232B1 (de) * 1974-05-24 1975-08-14 Vaw Ver Aluminium Werke Ag Verfahren zum Grafitieren von aus Hartbrandkohle bestehenden Formkoerpern
DE2457923C3 (de) * 1974-12-07 1981-11-05 Sigri Elektrographit Gmbh, 8901 Meitingen Graphitierungsofen
US4017673A (en) * 1974-12-17 1977-04-12 Sigri Elektrographit Gmbh Method and apparatus for graphitization of carbon materials

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FR2534240A1 (fr) 1984-04-13
IT8323145A0 (it) 1983-10-05
FI842235A (fi) 1984-06-04
DK113784D0 (da) 1984-02-28
YU43947B (en) 1989-12-31
DK164096B (da) 1992-05-11
IT8323145A1 (it) 1985-04-05
NZ205862A (en) 1986-12-05
ZA837487B (en) 1984-06-27
IN159953B (de) 1987-06-13
MX157341A (es) 1988-11-15
PT77451B (fr) 1986-04-09
DE3363084D1 (en) 1986-05-22
YU201483A (en) 1986-04-30
IE832345L (en) 1984-04-06
US4639929A (en) 1987-01-27
ES528150A0 (es) 1984-08-01
AU568097B2 (en) 1987-12-17
FI842235A0 (fi) 1984-06-04
AR241649A1 (es) 1992-10-30
ES526248A0 (es) 1984-06-16
WO1984001368A1 (fr) 1984-04-12
KR890003355B1 (ko) 1989-09-19
IE56122B1 (en) 1991-04-24
JPH0159207B2 (de) 1989-12-15
FI72114B (fi) 1986-12-31
PT77451A (fr) 1983-11-01
IT1167246B (it) 1987-05-13
YU152885A (en) 1988-04-30
YU44042B (en) 1990-02-28
GR79700B (de) 1984-10-31
ES8406377A1 (es) 1984-08-01
FR2534240B1 (de) 1984-11-23
DK113784A (da) 1984-06-04
TR21583A (tr) 1984-11-12
AU2072583A (en) 1984-04-24
DK164096C (da) 1992-10-05
ES8405727A1 (es) 1984-06-16
KR840006509A (ko) 1984-11-30
EP0121530A1 (de) 1984-10-17
CA1215504A (fr) 1986-12-23
JPS59501663A (ja) 1984-10-04
FI72114C (fi) 1987-04-13

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